Modren WRC machines sound tame in comparison.

eg.

[video]https://youtu.be/EeHCUZBXfXE[/video]

Boring answer: Better fueling and catalytic converters. The popping was unburnt fuel mixing with air and combusting as it left the exhaust so if you get the fueling right there shouldnt be any in the first place, and the catalyst should deal with the residual hydrocarbons.

Fueling for turbo’s is better rich than lean as the compression tends to result in detonation if you cant get it bang on, hence rally cars used to pop and bang a lot!

Control.

Back in the day, the Anti Lag systems were crude, they just left the throttle open, and cut the sparks a bit.

Today, the ALS systems use a much more subtle control system of bypass valves, ignition retard, and measure turbine speed to improve control linearity. They effectively run the engine as an external combustion system rather than the old “bang bang” uncontrolled rapid burn in the exhaust manifold.

It’s also worth noting, that modern cars don’t close the throttle during gear shifts and with rapid shifting boxes, don’t need anti lag on shift events

The “Cat” in a WRC is in the back box. It is effectively “dead” after the first stage as it is poisoned rapidly by the rich mixtures and high temperature.

All the WRC cars ran a cat, even back in the day, although as mentioned, it was there for show, rather than being for any actual reduction in tailpipe pollutants

[video]https://youtu.be/Qd6UsRY5bZ8[/video]

My neighbor drives a Toyota Yaris, she’s in her 80’s and whist she still drives like that ^ above as the amount of bashes and scrapes on her car will attest to, all I can say is thank **** it’s only a hybrid.

Did they have to have cats to make them “Road legal” so they could drive between stages ??

Audi A3 overtook me a few weekends ago, was popping and banging like a good’un. Drove and sounded like an utter dickhead.

DezB – Member

Audi A3 overtook me a few weekends ago, was popping and banging like a good’un. Drove and sounded like an utter dickhead.

Yeah, whilst the popping and farting exhaust seems to be a thing of the past in motor sport, it’s being wrote into the ECU of modern performance cars to try to give them some kind of character, like the office bore who wears a ‘funny’ tie.

I seem to remember some WRC/rallycross cars now use this type of ‘rocket’ system:

[video]https://www.youtube.com/watch?v=n_qCd6Lx7pE[/video]

[video]https://www.youtube.com/watch?v=8AtyZIiTUO0[/video]

Skip to 1m15s for a lunch from idle with full boost..

[video]https://www.youtube.com/watch?v=LpBiZYVfTp8&feature=youtu.be[/video]

Something to do with a pressurised air chamber in the engine bay, but that’s all I can recall.